Acute myelogenous leukemia (AML) is a blood cancer found mostly in adults that is characterized by abnormal cell growth and proliferation. It is estimated there will be 14,590 new cases of AML in the U.S. in 2013. Current chemotherapy treatments are able to cure on a fraction of all AML patients; and the five-year survival rate in patients over the age of 60 is a dismal 12%. The prognosis is worse if leukemia occurs secondary to an existing blood disease, known as a Myeloproliferative Neoplasm (MPN), with patients surviving an average of less than 3 months. Fortunately, a new chemotherapy agent, MLN4924, has entered clinical testing in AML and has demonstrated anti-leukemic effects in patients with various stages of disease. MLN4924 affects the intracellular pathways dysregulated in malignant cells to cause them to undergo programed cell death, also known as apoptosis. Our laboratory specializes in studying how chemotherapeutics such as MLN4924 induce apoptosis. The research plan proposed in this application, which is part of a larger research training plan in the field of molecular pharmacology, will use AML cell lines and clinical samples from newly diagnosed AML patients to investigate the exact mechanism by which MLN4924 induces apoptosis. Specifically, we will be studying how MLN4924 causes changes in the Bcl-2 family of proteins that are known to both positively and negatively regulate apoptosis. We will also study how these proteins change in leukemia cell lines developed from patients with pre-existing MPN. By understanding how these proteins are affected, we may be able to predict which AML patients will respond to MLN4924. Most of the leukemias in MPN patients also have a mutation in a signaling protein called JAK2, which causes the molecule to signal continually and enhance cell growth and survival. Ruxolitinib, a drug designed to inhibit this signaling, has entered clinical trials for treatment of MPN and leukemia arising from MPN. We will also test the combination of MLN4924 and Ruxolitinib in our MPN leukemia cell lines that have this JAK2 mutation. These studies will better define the therapeutic potential of these agents and advance our understanding of how they kill cancer cells on a molecular level. The long-term goal of these studies is to generate knowledge that will help scientists and clinicians develop and implement improved cancer therapies.